The purpose of this project is 1) to objectively evaluate the efficacy and clinical toxicity of drugs given to outpatients to alleviate apprenhension associated with dental procedures, 2) to study the physiological, psychological and biochemical responses to the stress of dental therapy, and 3) to evaluate the role of exogenous epinephrine administered with local anesthetic on cardiovascular performance. Special attention has been given to the non-invasive measurement of cardiac output and stroke volume by thoracic impendance cardiography. A recent study employing this methodology indicates that exogenous epinephrine administered with local anesthesia results in an increase in circulating epinephrine levels and that there is a concommitant increase in cardiac output. A parallel investigation indicated that the elevated epinephrine levels and elevated cardiac output are not attentuated by diazepam premedication. These findings suggest that exogenously administered epinephrine results in an increase in circulating levels and a resultant increase in cardiac output. A separate investigation demonstrated that the stress of surgery results in a measureable increase in plasma levels of beta-endorphin. Current investigations indicate that fentanyl and diazepam block this response while naloxone, an opiate antagonist, results in elevated beta-endorphin levels in comparison to placebo.